阅读说明：本技术 一种集成加热功能的方向盘离手检测传感器 (Steering wheel of integrated heating function is from hand detection sensor ) 是由 夏杨江 曹卫娟 施锦杰 于 2021-08-06 设计创作，主要内容包括：本发明公开了一种集成加热功能的方向盘离手检测传感器,其包括：电容式传感组件和控制组件,所述控制组件与电容式传感组件中的感应丝连接,并控制感应丝在感应采集状态与加热状态间切换。本发明提供的方案相对于传统设计节省了屏蔽层,使传感器感应垫更轻薄,可平滑地集成在方向盘内,且灵敏度不受影响。(The invention discloses a steering wheel hands-off detection sensor with integrated heating function, which comprises: the capacitive sensing device comprises a capacitive sensing assembly and a control assembly, wherein the control assembly is connected with an induction wire in the capacitive sensing assembly and controls the induction wire to be switched between an induction acquisition state and a heating state. Compared with the traditional design, the scheme provided by the invention saves the shielding layer, so that the sensor sensing pad is lighter and thinner, can be smoothly integrated in the steering wheel, and is not influenced in sensitivity.)

1. Steering wheel of integrated heating function leaves hand detection sensor, its characterized in that includes: the capacitive sensing device comprises a capacitive sensing assembly and a control assembly, wherein the control assembly is connected with one induction wire in the capacitive sensing assembly and can directly control the induction wire to be switched between an induction acquisition state and a heating state.

2. The integrated heating function steering wheel hands-off detection sensor of claim 1, wherein the control component comprises a ground component, a high-drive chip, and a capacitance processor; the grounding assembly is connected with the induction wire and controls the grounding state of the induction wire; the high-drive chip is connected with the induction wire and controls the power supply state of the induction wire, and the capacitance processor controls the grounding assembly and the high-drive chip to work in a coordinated mode so as to control the induction wire to be switched between an induction collection state and a heating state.

3. The integrated heating function steering wheel hands-off detection sensor according to claim 2, wherein the capacitance processor controls the grounding component to conduct grounding of the induction wire, and controls the high-drive chip to output heating current to the induction wire, so that the induction wire is in a heating state.

4. The steering wheel hands-off detection sensor with the integrated heating function according to claim 2, wherein the capacitance processor controls the grounding assembly to disconnect the grounding of the induction wire, and controls the high-drive chip to disconnect the current transmission with the induction wire, so that the induction wire is in a capacitance collection state, and the capacitance processor can collect external environment capacitance by charging and discharging the metal wire.

5. The integrated heating function steering wheel hands-off detection sensor of claim 2, wherein the grounding component is a MOS transistor.

6. The integrated heating-function steering wheel off-hand detection sensor of claim 2, wherein the grounding assembly is a relay.

7. The integrated heating function steering wheel hands-off detection sensor according to claim 1, wherein the capacitance processor controls the working state of the grounding component and the high-drive chip through an IO port.

8. The integrated heating function steering wheel hands-off detection sensor according to claim 1, wherein the capacitive processor controls the induction wire to switch between an induction collection state and a heating state through a time-sharing control strategy.

Technical Field

The invention relates to a sensing technology, in particular to a hand-off detection sensor for an automobile steering wheel.

Background

Currently, automatic driving of automobiles is rapidly developed, and some Advanced Driving Assistance Systems (ADAS) have been applied to automobiles in order to effectively improve driving safety. Steering wheel hands-off detection (HOD) is one type of ADAS, which is also a requirement of class L1-L4 automotive autopilot systems.

The steering wheel is away from hand detection, reminds the warning through detecting whether driver's hand leaves the steering wheel promptly to guarantee driving safety. Most of current HOD implementation methods are capacitive sensing methods, however, such detection methods have many disadvantages: the complex layout of the sensor leads to high cost, large occupied space and the like.

Since the capacitive sensor has high requirements on the surrounding environment, the sensitivity of the sensor may be affected by the surrounding grounded metal or wire, such as a steering wheel heating wire. Therefore, in the conventional design scheme, the off-hand detection sensor and the heating wire are independently arranged, and a thick shielding layer is additionally arranged between the off-hand detection sensor and the heating wire and used for shielding the influence of the heating wire on the sensor after being electrified, but the arrangement also increases the thickness of the sensor, so that the requirement on the space of the steering wheel is high, and the off-hand detection sensor cannot be suitable for all steering wheel suppliers.

Disclosure of Invention

Aiming at the technical problems existing between the existing steering wheel hands-off detection scheme and the steering wheel heating scheme, a new setting scheme for steering wheel hands-off detection and steering wheel heating is needed.

Therefore, the invention aims to provide a steering wheel off-hand detection sensor with integrated heating function, which can enable a sensor sensing pad to be thinner and lighter without reducing the sensitivity of the sensor by abandoning the conventional thick shielding layer.

In order to achieve the above object, the present invention provides a steering wheel hands-off detection sensor with integrated heating function, comprising: the capacitive sensing device comprises a capacitive sensing assembly and a control assembly, wherein the control assembly is connected with one induction wire in the capacitive sensing assembly and can directly control the induction wire to be switched between an induction acquisition state and a heating state.

In some embodiments of the invention, the control component comprises a ground component, a high-drive chip, and a capacitance processor; the grounding assembly is connected with the induction wire and controls the grounding state of the induction wire; the high-drive chip is connected with the induction wire and controls the power supply state of the induction wire, and the capacitance processor controls the grounding assembly and the high-drive chip to work in a coordinated mode so as to control the induction wire to be switched between an induction collection state and a heating state.

In some embodiments of the present invention, the capacitance processor controls the grounding component to conduct the grounding of the induction wire, and controls the high-drive chip to output the heating current to the induction wire, so that the induction wire is in a heating state.

In some embodiments of the present invention, the capacitance processor controls the grounding component to disconnect the grounding of the sensing wire, and simultaneously controls the high-drive chip to disconnect the current transmission with the sensing wire, so that the sensing wire is in a capacitance collection state, and the capacitance processor can collect external environment capacitance by charging and discharging the metal wire.

In some embodiments of the present invention, the ground component is a MOS transistor.

In some embodiments of the invention, the grounding assembly is a relay.

In some embodiments of the present invention, the capacitive processor controls the operating states of the ground component and the high-driving chip through one IO port.

In some embodiments of the present invention, the capacitive processor controls the induction wire to switch between the induction collection state and the heating state through a time-sharing control strategy.

Compared with the traditional design, the scheme provided by the invention saves the shielding layer, so that the sensor sensing pad is lighter and thinner, can be smoothly integrated in the steering wheel, and is not influenced in sensitivity.

The scheme provided by the invention has small requirement on the internal space of the steering wheel in specific application and is suitable for all steering wheel schemes.

The scheme provided by the invention integrates the functions of hand-off detection and heating of the steering wheel, and has stable and reliable performance and low cost.

Drawings

The invention is further described below in conjunction with the appended drawings and the detailed description.

Fig. 1 is a configuration example of a steering wheel off-hand detection sensor with an integrated heating function in the embodiment of the present invention.

Fig. 2 is a circuit diagram of an example of a steering wheel off-hand detection sensor with integrated heating function in an embodiment of the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further explained below by combining the specific drawings.

To set up steering wheel simultaneously in the current steering wheel and leave hand detection sensor and steering wheel heater strip scheme, the heater strip in the steering wheel is ground, and ground has the shielding effect to electric capacity, so both contacts together can influence electric capacity sensor sensitivity to make electric capacity sensor receive the heater strip influence after the circular telegram in the current steering wheel.

In view of the above, this scheme abandons the scheme that independently sets up the steering wheel heater strip in the current scheme, and the innovative adoption a wire is as the response silk promptly, is regarded as the heater strip simultaneously again, if can not only avoid independently setting up the heater strip to the influence of capacitive sensor sensitivity in the steering wheel after circular telegram, can also realize no longer setting up thick shielding layer to effectively reduce the whole volume of leaving hand detection sensor and steering wheel heating element in the steering wheel (need not to set up heater strip and thick shielding layer independently), but reduce cost simultaneously.

In view of the above, this scheme provides the steering wheel of integrated heating function and leaves hand detection sensor, and this sensor realizes response collection and heating based on a set of wire.

Specifically, the steering wheel hands-off detection sensor mainly comprises a capacitive sensing assembly and a control assembly, wherein the control assembly is connected with one induction wire in the capacitive sensing assembly and directly controls the induction wire to be switched between an induction collection state and a heating state.

The control component mainly comprises a grounding component, a high-drive chip and a capacitance processor.

The grounding component is connected with one end of the corresponding induction wire in the capacitive sensing component, and controls the grounding state of the induction wire, namely the grounding state of the induction wire can be conducted, so that the induction wire is grounded; or the grounding state of the induction wire is disconnected, so that one end of the induction wire is suspended.

In order to stably and reliably control the grounding state of the induction wire, in this embodiment, a MOS transistor or a relay is preferably used to form the corresponding grounding assembly, but not limited thereto.

The high-drive chip is connected with the corresponding induction wire in the capacitive sensing assembly, so that the power supply state of the induction wire can be controlled, the induction wire can be powered, and the induction wire is electrified and heated.

The capacitor processor of the grounding assembly controls the grounding assembly and the high-drive chip to work in a coordinated mode so as to control the induction wire to be switched between an induction acquisition state and a heating state.

Specifically, this electric capacity treater switches on the ground connection of response silk through control ground connection subassembly, and the chip output heating current is driven to the response silk to the control height simultaneously, makes the response silk be in heating state.

This electric capacity processor control accessible control ground connection subassembly disconnection response silk ground connection, the high current transport of driving chip disconnection and response silk of simultaneous control makes the response silk be in electric capacity collection state, electric capacity processor accessible charges and discharges the wire, gathers external environment electric capacity.

When the capacitance processor is implemented, the induction wire can be controlled to be switched between an induction acquisition state and a heating state through a time-sharing control strategy.

By way of example, the control operation can be realized by clock slices, a time period is divided into T1 and T2, only capacitance is collected in T1, only heating is carried out in T2, and the heating rate is determined by matching T1 and T2.

In the steering wheel hands-off detection sensor formed by the method, the induction wire is controlled by the on-off of a grounding component (such as an MOS (metal oxide semiconductor) tube and a relay) and a software strategy to realize time-sharing work: switching between an induction acquisition working state and a heating working state; when the capacitor is collected, the connection with the ground is disconnected, the ground interference is shielded, and the capacitor is not collected when the capacitor is heated.

The present solution is described below by way of the following specific example.

Referring to fig. 1, an example scenario of a steering wheel off-hand detection sensor with integrated heating function is presented.

As can be seen, the steering wheel off-hand detection sensor 100 mainly includes an SBC circuit 110, a capacitance processor (MCU)120, a MOS transistor 130, a load driver 140, and a wire 150.

SBC circuit 110 integrates the power supply circuit and LIN functions, and converts the 12V external input into 3.3V power that can be processed by a capacitance processor (MCU).

The MOS transistor 130 is controlled by a capacitance processor (MCU)120, and is used to control the grounding state of the wire 160. For example, in the heating state, it is responsible for grounding the wire 160; when the capacitance is collected, it is responsible for disconnecting the disconnection wire 160 from the ground.

The load driver 140 is a high-driving chip 140, and is controlled by a capacitance processor (MCU)120 to control the heating state of the metal wire 160. For example, when the induction heating wire is in a heating state, 12V of electricity is output to the induction wire; when the capacitance state is collected, the induction wire is controlled to be suspended.

In this example, the capacitance processor (MCU)120 may integrate the capacitance collection module and the crystal oscillator to control the whole module, including switching the heating function of the capacitance collection module, collecting the capacitance, and communicating with the outside.

As shown in fig. 2, an example of a circuit design is shown for implementation of the present example embodiment.

As can be seen from the figure, the capacitance processor (MCU)120 here is composed of corresponding MCU chips, and when the MCU chips are disposed in cooperation with the MOS transistor 130 and the high-driving chip 140, an IO port is used to simultaneously control the high-driving chip and the MOS transistor to be turned on and off.

Specifically, an IO port of the capacitance processor (MCU)120 is connected to a gate of the MOS transistor 130 and an INPUT port of the high-driving chip 140 at the same time.

Meanwhile, the source of the MOS transistor 130 is grounded, and the drain of the MOS transistor 130 is connected to the middle of the wire 150.

One end of the wire 150 is connected to the OUTPUT port of the high-driving chip 140, i.e. the OUTPUT port of the high-driving chip 140, and is connected to 12V or disconnected depending on the high-driving chip 140. The middle of the wire 150 is connected to the ground through the MOS tube 130, and the MOS tube determines whether to be connected to the MCU capacitance acquisition AD port or the ground. The other end of the wire 150 is connected to a capacitance AD acquisition port of the capacitance processor (MCU) 120.

In the scheme thus configured, the capacitance processor (MCU)120 controls the operating states of the MOS transistor 130 and the high-side driver chip 140 through one IO port.

Thus, when the IO port of the capacitance processor (MCU)120 outputs a high level, the high-driving chip 140 outputs 12V to the metal wire 150; and the MOS tube is opened, and the source and the drain are conducted, so that the metal wire 150 is grounded, and the driving of the MOS tube 130 and the high-drive chip 140 are simultaneously opened, so that the two ends of the metal wire are 12V and GND, the metal wire 150 at this time is in a heating state and serves as a heating wire, and the metal wire does not collect a capacitor at this time.

When the IO port of the capacitance processor (MCU)120 outputs a low level, the MOS transistor is turned off, the source and the drain are turned off, so that the metal wire is suspended, the high-driving chip 140 is suspended, the driving MOS transistor 130 and the high-driving chip 140 are simultaneously turned off, at this time, one end of the metal wire is suspended, one end of the metal wire is connected to the capacitance AD acquisition port of the capacitance processor (MCU)120, and at this time, the metal wire is in an induction acquisition state and is used as an induction wire. In this state, the metal wire may be charged and discharged by the capacitance processor (MCU)120, and the external environment capacitance is collected, at which time the metal wire is not heated.

Meanwhile, a control strategy is set in the capacitance processor (MCU)120, a time period is divided into T1 and T2, only capacitance is collected in T1, only heating is carried out in T2, and the heating rate is determined by T1 and T2.

Accordingly, the embodiment can be implemented by a MOS transistor andload chip (i.e. theHigh-drive chip) Switch (2)The switching of the acquisition capacitor and the heating function is realized. MOS tube and load chip controlled by capacitance processor (MCU)(i.e. theHigh-drive chip)Simultaneously open and close.

When the MOS tube is closed, the connection between 12V and the ground is disconnected, the MOS tube is connected to the capacitor AD acquisition port only through a current-limiting resistor, the metal wire serves as an induction belt to acquire the capacitor, and whether the hand leaves the steering wheel or not is judged according to the size of the capacitance value. Specifically, the metal wire is charged through the MCU capacitor AD acquisition port, the metal wire serves as a capacitor anode, the ground serves as a capacitor cathode, a capacitor to the ground is formed, the capacitor formed by hands charges a large capacitor with a known capacitance value, and after the large capacitor is fully charged, the number of charging times is combined, and the human body capacitance value is obtained through calculation.

When the MOS tube is opened, the two ends of the metal wire are 12V and the ground, and the metal wire with small resistance and large power is selected, so that the metal wire can rapidly generate heat in the mode and serves as a heating function.

Meanwhile, the MCU millisecond-level fast switching MOS tube is used for switching on and off, so that the functions of collecting capacitance and heating can be realized simultaneously.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.